基于恒压微流泵系统的微液滴分选

发布时间：2018-07-02 23:03

本文选题：液滴微流控 + 恒压驱动　；参考：《东南大学》2016年硕士论文

【摘要】：液滴微流控是微流控技术的一个重要的分支,对液滴的操控如液滴融合、裂分、混合、分选、捕获等技术具有非常重要的意义,液滴分选就是从大量液滴中分离出目标液滴,可以用来提纯、浓缩目标液滴。微液滴生成和操控的前提条件是稳定的流体驱动,流体的驱动方式多种多样,常用的驱动方式是注射泵,但它有许多固有的缺点,比如分配过程易受温度变化、胶内气泡、螺杆转速的影响,而且纹波比较大、单个注射器流量范围小。气压驱动泵比注射泵的纹波小,响应速度快,但是目前市场上的气压驱动泵价格昂贵,控制范围不大。欲实现兼具这些优点的气压泵,本论文研制了一台适用于微流控领域的双气缸的恒压微流泵。两个气缸的气压控制完全独立,适用于液滴微流控研究。与现有的一些气压泵相比,恒压微流泵的气压控制范围广、精度较高、气压稳定、响应速度快。稳定时的气压波动范围为±1 mbar,气压控制范围为0.0～10.0 bar。可以用两款上位机软件和它进行WiFi通信,用户可以选择使用PC机或安卓平板电脑,上位机软件实时记录实验数据,可以提示各种运行参数,具有友好的交互界面。使用CAD软件设计了两种液滴分选芯片,分别利用了压电陶瓷的逆压电效应和非均匀电场对液滴的介电泳力,利用恒压微流泵搭建了液滴分选系统。首先利用搭建的液滴分选系统生成液滴,研究了气压为0～240 mbar时液滴直径、液滴生成速度与油相水相气压之比的关系。发现当油相气压值固定时,油相和水相气压比值越大,液滴直径越小,液滴生成速度也越慢;而当油相与水相气压比值相同时,油相气压越大,液滴直径越小,液滴生成的速度也越快。利用搭建的液滴分选系统,用设计的两种微流控芯片做了液滴分选。基于压电陶瓷的分选芯片在气压为0～200mbar时给PZT加单个脉冲,改变总持续时间T和高电平时间Th能够实现单个液滴分选,目前可以实现11 Hz的液滴流中对单个液滴的分选。然后当油相气压为10000 mbar,水相为1000 mbar时生成305 Hz的液滴,对PZT施加连续的方波,发现可以分选,且分选率会随着高电平持续时间Th增加而增加。基于介电泳的分选芯片在气压为0～450 mbar时给金电极施加合适的电压幅值和频率,可以把液滴全部拉到目标流道中。且达到全分选时电压幅值越高频率就要降低。当电压过高或者频率过大时可能使液滴碎裂,故需要选择好参数。恒压微流泵系统适合作为微流控的驱动。基于恒压微流泵系统的液滴分选是比较基础的研究,为以后高速微液滴分选打下基础。
[Abstract]:Droplet microfluidic is an important branch of microfluidic technology. Droplet control, such as droplet fusion, fracturing, mixing, sorting, trapping and so on, is of great significance. Droplet sorting is the separation of target droplets from a large number of droplets. Can be used to purify, concentrate the target droplets. The prerequisite for the formation and control of microdroplets is stable fluid drive, which is often used in injection pumps, but it has many inherent disadvantages, such as the distribution process is susceptible to temperature changes, bubbles in the gel, Screw speed, and the ripple is relatively large, a single syringe flow range is small. The ripple of pneumatic drive pump is smaller than that of injection pump, and the response speed is fast, but the price of pneumatic drive pump is expensive and the control range is not large. In order to realize the pressure pump with these advantages, a double cylinder constant pressure microflow pump suitable for microfluidic control is developed in this paper. The pressure control of the two cylinders is completely independent and suitable for droplet microfluidic research. Compared with some existing air pressure pumps, the constant pressure microflow pump has the advantages of wide air pressure control range, high precision, stable air pressure and fast response speed. The range of pressure fluctuation is 卤1 mbar. and the control range is 0.010 bar. when the pressure is stable, the range of pressure fluctuation is 卤1 mbar. Two host computer software and it can be used for WiFi communication, users can choose to use PC or Android tablet computer, PC software records the experimental data in real time, can prompt a variety of operating parameters, with a friendly interactive interface. Two kinds of droplet sorting chips were designed by using CAD software. The inverse piezoelectric effect of piezoelectric ceramics and the dielectric electrophoretic force of non-uniform electric field on the droplet were used respectively, and the liquid drop sorting system was built by using the constant pressure microflow pump. Firstly, the droplet was generated by the designed system, and the relationship between the droplet diameter, droplet formation velocity and the ratio of oil to water pressure was studied when the air pressure was 0 ~ 240 mbar. It is found that the larger the ratio of oil to water pressure is, the smaller the droplet diameter is and the slower the droplet formation rate is when the pressure ratio of oil phase to water phase is fixed, while the larger the pressure ratio of oil phase to water phase is, the smaller the droplet diameter is. The faster the droplets form. Using the designed droplet sorting system and two microfluidic chips designed, the droplet sorting is carried out. A single pulse is added to the chip based on piezoelectric ceramic when the pressure is 0~200mbar. The single drop can be sorted by changing the total duration T and the high level time Th. At present, the single drop can be sorted in the droplet flow of 11 Hz. Then, when the pressure of oil phase is 10000 mbarand the water phase is 1000 mbar, 305Hz droplets are generated, and the continuous square waves are applied to PZTs.It is found that the separation rate increases with the increase of high level duration Th. The separation chip based on dielectric electrophoresis can apply the appropriate voltage amplitude and frequency to the gold electrode at the pressure of 0 ~ 450 mbar, which can pull all the droplets into the target channel. The higher the voltage amplitude is, the lower the frequency will be. When the voltage is too high or the frequency is too high, the droplets may be broken, so we need to select good parameters. The constant pressure microflow pump system is suitable for microfluidic drive. The separation of droplets based on the constant pressure microflow pump system is a relatively basic study, which will lay the foundation for the separation of high speed microdroplets in the future.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN492

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